I'm two weeks in with mine now, it's great! I use it almost exclusively with M-mount lenses, but have a 20 as well. Tomorrow I'll go back to the ZM and let my wife use it with the 20. She'll go full auto but is great with composition, so I'm interested to see what she can do with it but at the same time worried I won't get it back. 😀
Great camera! It's certainly no M8/9 substitute and also could never replace my ZM, (and I'm not opening the Film vs. Digital can of worms). It has already found its own place, being fun to use colour digital. However, it also seems sufficient to replace an entry level DSLR for my day to day purposes, and as a result my D40 is already considering a new home. If I ever take my dream photo safari trip I'll rent a high end DSLR anyway so why keep a camera I'm not using?
I picked up the electronic viewfinder too. We both like it and seem to use it about half of the time, if not more. I filled up my flickr account between ZM and GF-1 in October, but can start posting again on Monday. 🙂
Cheers,
Rob